Method of processing coal



March 12, 1935. H. STEVENS v y 1,993,756

vMETHOD 0F PROCESSING GOVAL Original Filed-Jan. 14, 1924 .2 Sheets-Sheet1 unc-nx Illllllll Hull-n ull-nu Munn March 12, 1935. H. STEVENS METHODOF PROCESS-ING COAL 2 Sheets-Shea?l 2 Original Filed Jan. 14, 1924 Elllllllllllllllllllill I IIIIIIIIIIH Patented Mar. 12, 1935 NITED STATESMETHOD OF PROCESSING COAL Harold Stevens, Cincinnati, Ohio, assignor, bymesne assignments, to Harold Stevens, trustee Application January 14,1924, Serial No. 686,053

Renewed May 2.7, 1933 2 claims.l (C1. 2oz-13') This invention relates toa method for processing coal and the like whereby it is freed from allvolatile oils and gas and a high grade of metallurgical coke isproduced.

In carrying out of my invention I employ electricity as the heatingagent by placing a suitable resistor element entirely through the chargeof coal to be heated, said resistor becoming highly heated thereby.

I have discovered that coals have various electrical properties, andsome coals are resistors o'f electricity, and also become conductorswhen suiciently heated.

When the coal contacting with the resistor becomes heatedit alsoconducts electricity which in turn heats the particles of coal so thatthe conductivity of the mass of coal in the charge and the heatgenerated thereby moves outwardly from the resistor element until themass of the charge is completely heated, which releases the volatile oiland gas contained in the charge.

In carrying out my invention I provide a steel retort preferablycylindrical in shape which isl divided coke, with the ends of whichsuitable electrodes contact, the retort is then lled with finely crushedcoal which completely Asurrounds the resistor element. The volatilematter is conducted from the retort to a series of condensers wherein itis cooled and condensed to liquid form, which by reason of the reducedpressure allows the vapor in the retort to pass therefrom.

These and other features of my invention are hereinafter more fullydescribed, and are illustrated in the accompanying drawings in which:

Figure 1 is a vertical central section showing diagrammatically asuitable apparatus, embodying my invention. A

Figure 2 is a longitudinally vertical section of my improved retort, onan enlarged scale.

In these drawings A indicates a steel cylinder on the ends of which aresuitably secured metal heads A. The interior of the cylinder A, andheads A are provided with a lining a of refactory material adapted toresist intense heat. The

heads A are also electrically insulated by means of a layer of asbestos,a', or other suitable material, see Fig. 2. The heads A' and theirlinings are provided with openings through which is inserted a resistorelement B of any suitable mate- 5 rial, but preferably composed of apaper or'wood tube bf lled with finely divided coke b' against whichelectrodes C contact. These electrodes pass through suitableguidelsleeves secured to the outside of the heads A by means oftap-screws d, said sleeves D being properly electrically insulated fromthe'heads A'. The interior of the sleeves D is also provided withinsulation material cl.

The outer ends of the electrodes C are pro-` l5 vided with cross bars E,to the ends of which are attached retracting springs F, which are alsoattached to the tap-screws d, `so that in case of shrinkage of the nelydivided coke b lconstituting the resistor -B the electrodes C will becaused to follow it up, and keep it compactly pressed together-and thusavoid undue arcing.

From the two electrodes C conductors G lead to an adjustable transformerI-I, by means of l which the current supply'to the resistor B` can 25`be regulated as may be desired.

The cylinder A is provided with suitable manhole openings A2, throughwhich crushed coal B see Fig. 2, can be placed in the retort, enoughbeing placed therein to ll it asV full as possible. These man-holes are.provided with covers a2 which are secured in place by means of clampsA3 so as to resist the pressure of the vapor and gas released by thecoal.

'Ihis vapor and gas is carried from the retort 35 by a pipe J by whichit is conveyed to a series of connected condensers K, K' and K2. Theoutlet pipe J is provided with a valve J2 by means of which the escapeof gas from the condenser K2 can be'controlled or prevented as desired.40

In operation, the retort A having been filled with nely crushed coal asdescribed, and closed so that no gas can escape, electricity is thencaused to pass through the the column of finely dividedcoke composingthe resistor B thereby generating heat which is communicated to theparticles immediately contacting therewith, and

as the coal becomes hot. gas is thrown off, which .quickly raises thepressure in the retort and conwas confined to the resistor B, it hasgradually spread until the entire mass of coal has become a conductiveresistance and a heat generator.

In the meantime the vapor and gas Yreleased from the coal havebuilt up asufficient pressure to raise the temperature within the retort to anydesired degree, the increased gas pressure around the chains of seriesof contact arcs produces extremely high temperature.

The vapor and gas, upon entering the condensers, liquefy at thedifferent stages of reduction of temperature, thus forming A differentgrades of light and heavy oil, and tar.

It will be observed that I employ intense heat generated by theconversion of electric energy into heat energy by means of an easilyremovable resistor element which extends through the mass of materialcontained within a pressure retort.

By means of my invention it is possible to vary the proportion of heatradiating surface of the material undergoing distillation. For examplethis may be done by varying the current density through adjustment ofthe transformer H where alternating current is employed. By adjustmentof the transformer it is possible to use only the initial resistor asthe heating element or to increase the diameter of the heating elementto any desired extent. In other Words, the amount of energy put indetermines the temperature and, therefore, the extent to which coking ofthe surrounding coal is carried. Thus the diameter of the heatingelement can be controlled, the greater the diameter of the heatingelement the greater the radiating surface thereof.

Another advantage of my invention is that it provides means for thevaporization of the volatile products under the pressure of selfgenerated vapors thereby increasing the yield of liquid organiccompounds, especially of those having low specic gravity and boilingpoints, particularly those products suitable for use in internalcombustion engines.

My inventionis based on the fact that all coals which show, on chemicalanalysis, a carbon-hydrogen ratio` of twenty-six, or less, have a highd-electric strength.

While I have shown but one resistor element, I can use a plurality ofresistor elements if desired, the placing of the same being inaccordance with the fundamental equation regarding the linear motion oftravel of heat, the resultant coke showing, on examination ofcross-section a series of perfect annuli as distinguished from thelngery coke produced by the present process.

When a temperature below 750 C., is used the resistor element may becomposed of amorphous carbon or suitable metallic tubes coated oralloyed with tin, bismuth or cadmium, which are capable of acting asreducing elements with the free hydrogen evolved, thereby changing tarryacids into neutral compounds of great commercial Value.

When temperatures above 750 C. are employed,'the resistors are composedof columns of coke, free from. volatile matter, contained in cellulosetubes. Heat is generated by the resistance of particles of coke and theconsequent chains of series and multiple-contact arcs establishedtherein.

Increased gas pressure surrounding these arcs produces extremely hightemperature and causes changes of great magnitude through the syntheticreconstruction and polymerization of the xed gases.

I prefer to use alternating current for thermal purposes, efficiencybeing obtained by resolving the current into as large a number of phasesas possible, consistent with the mass of charge, or mechanical detailsof retort construction.

By employing a simple arrangement of switches, which form no part ofthis invention, a polyphase current can be changed to single phase whendistillation has advanced to a point where it is found that single phasecurrent is desired. Direct current can be used alternately withalternating current to aid in the electro-synthetic formation of variousorganic compounds.

Because of the strength of the steel shell A of the retort, and theconsequent freedom from hazard of explosion and fire, I am able toconduct the distillation, by means of suitably controlled valves, underpressure of self-generated gas, the pressure being maintained on thevapors, through their course from the report and through the condensers.

The pressure control, temperature of vapor, and electro-decompositionsecure the conversion of the diierent hydrocarbons into light oil of lowspecic gravity and low boiling point.

Before commencing the process of distillation it is advisable thatdesired pressure be built up with hydrogen gas by the use of mechanicalmeans, to the desired point, after which the vapors generated lwillmaintain the desired pressure.

The diierent steps in the process and operation of my apparatus, asabove described may be varied as taught by experience, to meet differentconditions, materials and results desired.

Having thus fully described my invention and suitable apparatus forutilizing the same, wha'- I Y claim as new and desire to secure byLetters Patent is:

1. The process of carbonizing a mass of solid carbonizable material in aclosed retort in the presence of a catalyst operating to alter tarryacids to substantially neutral compounds, which comprises carbonizingthe mass from the interior thereof by providing and maintaining a denitepath for electrical current within and through the mass, and in passingan electric current through said path whereby the mass of the materialis heated from. within outwardly and the carbonized material becomes apart of said path.

2. 'I'he process of carbonizing a mass of solid carbonizable material ina closed retort in the presence of an electrically-conductive catalystoperating to alter tarry acids to substantially neutral compounds, whichcomprises heating said `catalyst by passing an electric current there-HAROLD STEVENS.

